To avoid generation of burrs and naps at the final part of the processing.

A method for producing a paper container wherein a blanks block 3 is formed by accumulating a plurality of sheets of carton blanks 1 under extended condition and an additional processing is applied on the outer peripheral part of a plurality of sheets of the carton blanks 1 by rotating a rotating blade 6 moving from the starting part 4 of the processing to the final part 5 of the processing along the outer periphery along the press direction on the carton blanks so as to discharge cut parts 7 to the moving direction side and cutting a part of the periphery of the blanks block 3, is provided and under a condition where the final part 5 of the processing of the blanks block 3 is cut in advance by moving the rotating blade 10 toward the starting part 4 side of the processing, the rotating blade 6 is moved from the starting part 4 of the processing of the blanks block 3. It is possible thereby to avoid generation of burrs and naps on the carton blanks 1 at the final part 5 of the processing.